1. Field of the Invention
The invention relates to implant devices and instruments used to repair body tissue. In particular, the invention relates to an implant device, instruments and methods for repairing body tissue during endoscopic surgical procedures. Still more particularly, the invention relates to implant devices, instruments and methods for repairing meniscal tissue during arthroscopic surgery of the knee.
2. Description of the Prior Art
Implant devices for repairing body tissue are known in the prior art. While such devices may be classified into several categories, the present invention is related to elongated devices having transversely extending barbs or projections which assist in retaining the implant in place within a tissue defect (e.g. a tear) to hold body tissue in close approximation during the healing process.
One such known device is described in U.S. Pat. No. 4,873,976 (Schrieber). This device comprises a solid elongated shaft having a plurality of transversely extending projections, a pointed tip and a transverse circular head at its proximal end.
Other similar devices are disclosed in U.S. Pat. Nos. 4,884,572; 4,895,148; 4,924,865; and 4,976,715 all issued to Bays et al. The devices disclosed in these Bays et al. patents primarily differ from the Schrieber device in that they are cannulated. The Bays et al. patents are assigned to the assignee hereof and, along with Schrieber, are incorporated by reference herein.
All of the above described elongated devices are arrow-like and are designed to be inserted or pushed into tissue to be repaired. The devices are sometimes referred to as xe2x80x9ctissue anchorsxe2x80x9d because they hold tissue together during healing. While these devices are intended to be used during arthroscopic or more generally endoscopic procedures, that very fact makes the insertion sometimes difficult. It is known to use elongated cannulas to guide the implants into position and smaller push rods to push them in. In the Schrieber type device, the implant is pushed through a cannula with an elongated pusher sized to be slidingly received within the cannula. With devices such as those disclosed in the Bays et al. patents the implant device is secured to the distal tip of a holding device and pushed into place, with or without the use of a guiding cannula.
All such arrow-like implant devices must not only enter tissue easily, but must resist migration once situated in place. Consequently, it is an object of this invention to provide a tissue anchor which has barbs to facilitate insertion and has a head design to minimize distal migration.
It is desirable to simplify the insertion process for these types of push-in arrow-like implant devices. It is also desirable to make such modifications to prior art arrow-like implant devices and systems as may improve their use and performance during and after (i.e. during healing when retention within tissue is important).
Accordingly, it is a further object of this invention to develop a tissue repair system incorporating a cannulated push-in implant or tissue anchor device, preferably bioabsorbable, and a simplified insertion apparatus, preferably operable by one hand.
It is also generally an object of this invention to provide a tissue anchor inserting device and method for guiding and inserting a cannulated tissue anchor into position at a surgical site.
It is another object of this invention to provide an elongated inserting device for receiving therein a cannulated tissue anchor, preferably at its distal end.
It is still another object of this invention to provide an elongated inserting device suitable for endoscopic procedures and capable of being operated from its proximal end.
It is also an object of this invention to provide a tissue anchor inserting system which facilitates the assembly of an inserting device with a cannulated tissue anchor.
It is yet another object of this invention to provide such a system with a holder for retaining a tissue anchor to facilitate such assembly.
These and other objects are accomplished by the preferred embodiment of the system disclosed herein which comprises a tissue anchor component, an inserter component and a package component. The tissue anchor component is a device comprising an elongated shaft having a proximal end, a distal end and a longitudinally extending bore therethrough. A plurality of barbs is longitudinally spaced along the shaft and the barbs are tapered in a distal direction to facilitate distal movement of the shaft through tissue material. The barbs are aligned in at least one row (preferably four rows) on the external surface of the shaft and a transversely extending head is situated at the proximal end of the shaft. The head has an aperture aligned with the bore and is generally elongated along a major axis which is misaligned relative to at least one of the rows of barbs.
The invention also resides in a tissue anchor inserter component and method for using the inserter with a cannulated tissue anchor. The inserter comprises a housing, a first elongated tubular shaft extending distally from the housing, the shaft having an axially aligned bore therethrough and an elongated needle adapted to be slidably received within the bore. The shaft is adapted to receive a cannulated tissue anchor while the needle is adapted to be received in the bore of the anchor. A trigger means is provided for moving the distal end of the needle between a first, retracted position, in which the needle is maintained within the bore, and a second, extended position, in which the needle is extended distally, beyond the bore. A pusher rod for pushing the anchor out of the device is adapted to be slidably received within the bore and moved between a first, retracted position, in which the distal end of the pusher rod is maintained within the bore of the shaft, and a second, extended position, in which the distal end of the pusher rod is adjacent the distal end of the shaft.
The inserter component is used to perform the method of inserting a cannulated tissue anchor into tissue to be treated at a surgical site. The method comprises the steps of providing a cannulated tissue anchor and providing a tissue anchor inserter as described above. The method further comprises providing the tubular shaft with a receiving chamber, for slidably receiving the needle and the tissue anchor, and a pusher means for engaging the tissue anchor to push it out of the receiving chamber. The needle is then extended distally from the receiving chamber, inserted into the bore of the tissue anchor and then retracted with the tissue anchor into the receiving chamber. The surgical site at which the tissue anchor is to be placed is located and the needle is extended from the receiving chamber into tissue at the surgical site. The pusher means is advanced distally to push the tissue anchor distally along the extended needle and into the surgical tissue. The procedure is completed by removing the needle from the tissue.
The invention also resides in a combination package and loading component which is a device for retaining a cannulated tissue anchor and facilitating its assembly with the above described inserter. The package comprises a base and a funnel means, the base having a first surface for receiving a cannulated tissue anchor thereon in predetermined orientation and the funnel means for being aligned with the bore of the tissue anchor to facilitate insertion of the inserter needle into the anchor. The package further comprises a releasable holding means having a second surface for holding the tissue anchor in alignment with the funnel until the assembly of the anchor with the inserter has been completed.